Heart failure is a condition which affects thousands of people throughout the world. Put into the most simple terms, congestive heart failure is the inability of the heart to pump blood at an adequate rate in response to the filling pressure. Such a condition can have many consequences, including congestion in the tissues, peripheral as well as pulmonary edema, and shortness of breath. In its most severe stages, congestive heart failure results in death.
For this reason, many attempts to treat heart failure have been tried. These past attempts include both electrical stimulation as well as drug therapy or both in combination. See for example, Bennett et al. U.S. Pat. No. 5,213,098 (electrical stimulation) or Kramer U.S. Pat. No. 5,405,362, White U.S. Pat. No. 4,360,031, Ellinwood U.S. Pat. Nos. 3,923,060 or 4,003,379 (electrical stimulation and drug therapy)
To date drug therapy is the method of treatment which has enjoyed the greatest success. Such drug therapies include, for example, diuretic agents and angiotensin converting enzyme inhibitors. One particular method which has been found to be somewhat effective in reducing the symptoms of heart failure is intermittent use of nitroglycerin to the body.
Although various drug therapies may be effective in select patients, often such a treatment in many cases has limited effectiveness or is difficult to administer or both. For example, nitroglycerin is only effective if administered at the right time and therefor usually requires physician supervision and can lead to a number of side effects including hypotension.
Thus it would be desirable to provide a way to detect and quantitatively monitor the degree of congestive heart failure. Such quantitative monitor should be sensitive to early changes of heart failure and both easy and convenient to use, and require little or no physician supervision. It is a further goal to provide an automatic method and device for treating congestive heart failure which uses such a quantitative monitor.